The present invention relates to a semiconductor device and a method for manufacturing the same and, more particularly, to a semiconductor device having a chip-size package structure separated from a semiconductor device having a wafer-scale package structure in which the wafer has already been resin-sealed with individual chip regions thereof and formed with external electrodes and a method for manufacturing the same.
Recently, spread of portable electronic apparatuses has been accelerated toward smaller portable electronic apparatus. Development of faster computer apparatuses is also accelerated. In order to achieve compactness and high speed, efforts have been made to reduce delay time associated with signal propagation by reducing the length of wires led out from semiconductor devices loaded on such apparatuses. Such efforts are focused on the development of semiconductor devices having a semiconductor package in the size of a pellet referred to as "chip-size package" (including devices in sizes slightly greater than the pellet size).
FIG. 9 is a schematic perspective view of an example of a conventional semiconductor device having a chip-size package structure. FIG. 10 is a schematic enlarged sectional view of a peripheral part of the semiconductor device shown in FIG. 9.
FIG. 11 shows an example of a semiconductor pellet in which a semiconductor element, wirings, electrode pads, a passivation film, etc are formed.
In FIGS. 9 and 10, reference numeral 80 designates a semiconductor pellet which comprises a semiconductor substrate 1 formed with semiconductor devices 91, wirings 92, electrode pads 93, a passivation film 94, etc., as shown in FIG. 11, for example. Reference numeral 2 designates a tape insulation layer bonded on to the passivation film on the pellet 80 so as to cover regions thereof except a peripheral region, and reference numeral 3 designates a plurality of wiring patterns formed on the tape insulation layer 2, some of the patterns being electrically connected to a part of a plurality of electrode pads formed on the semiconductor pellet although not shown.
Reference numeral 6 designates external electrodes in the form of balls provided on a part of the wiring patterns 3 in electrical connection thereto. Reference numeral 8 designates bonding wires for connection between electrode pads 7 formed on the peripheral area of the pellet 80, i.e., the region of the pellet 80 which is not covered by the tape insulation layer 2 and the wiring patterns 3 on the tape insulation layer adjacent thereto. Reference numeral 9 designates resin bonded and hardened so as to seal the bonding wires 8 and the electrode pads 7 and wiring patterns 3 to which bonding wires are connected by bonding on both ends thereof.
In a semiconductor device having a chip-size package structure as described above, since the wiring in the pellet 80 is led out by the bonding wires 8 from the wiring patterns 3 in the peripheral area of the pellet, wires led out from electrode pads 7 near the pellet center can become so long as to delay signals.
Further, since the wires are led out only at the peripheral area of the pellet 80 and the maximum number of pins (the maximum number of the external electrode 6) is determined by limitations placed on the width and intervals of the wiring patterns 3, this structure has a problem in that it is not compatible with smaller pellets with an increased number of external electrodes.
Furthermore, the external electrodes 6 can not be provided on the region for leading out wires on the pellet and the intervals between the external electrodes must be small. This increases difficulty in soldering the semiconductor device having the chip-size package structure to connect it to a printed circuit board during mounting of the same.
Meanwhile, a proposal has been made on the manufacture of a pellet-size semiconductor device in which individual chip regions (pellet regions) are resin-sealed and formed with external electrodes while the chip regions are on a semiconductor wafer to produce a semiconductor device having the wafer-scale package structure which is in then divided (cut) into individual semiconductor devices in the pellet size.
Such a method of manufacture makes it possible to simplify the manufacturing steps and to provide a low-cost and compact semiconductor device having the chip-size package structure. However, there is still a need for increased reliability and reduced cost.
As described above, problems have arisen in a conventional semiconductor device having a chip-size package structure in that wires led out from electrode pads near the pellet center have a large length which can delay signals; the structure is not compatible with small pellets having an increased number of external electrodes; and difficulty is increased in soldering it on a printed circuit board to connect thereto during mounting.